title: Corneal cross-linking in 9 horses with ulcerative keratitis.
abstract: BACKGROUND
  Corneal ulcers are one of the most common eye problems in the horse and can cause varying degrees of visual impairment. Secondary infection and protease activity causing melting of the corneal stroma are always concerns in patients with corneal ulcers. Corneal collagen cross-linking (CXL), induced by illumination of the corneal stroma with ultraviolet light (UVA) after instillation of riboflavin (vitamin B2) eye drops, introduces crosslinks which stabilize melting corneas, and has been used to successfully treat infectious ulcerative keratitis in human patients. Therefore we decided to study if CXL can be performed in sedated, standing horses with ulcerative keratitis with or without stromal melting.
  
  
  RESULTS
  Nine horses, aged 1 month to 16 years (median 5 years) were treated with a combination of CXL and medical therapy. Two horses were diagnosed with mycotic, 5 with bacterial and 2 with aseptic ulcerative keratitis. A modified Dresden-protocol for CXL could readily be performed in all 9 horses after sedation. Stromal melting, diagnosed in 4 horses, stopped within 24 h. Eight of nine eyes became fluorescein negative in 13.5 days (median time; range 4-26 days) days after CXL. One horse developed a bacterial conjunctivitis the day after CXL, which was successfully treated with topical antibiotics. One horse with fungal ulcerative keratitis and severe uveitis was enucleated 4 days after treatment due to panophthalmitis.
  
  
  CONCLUSIONS
  CXL can be performed in standing, sedated horses. We did not observe any deleterious effects attributed to riboflavin or UVA irradiation per se during the follow-up, neither in horses with infectious nor aseptic ulcerative keratitis. These data support that CXL can be performed in the standing horse, but further studies are required to compare CXL to conventional medical treatment in equine keratitis and to optimize the CXL protocol in this species.
authors.affiliation: Department of Animal Environment & Health, Swedish University of Agricultural Sciences, PO Box 234, SE-532 24 Skara, Sweden. anna.hellander.edman@slu.se
authors.forename: Anna
authors.initials: A
authors.lastname: Hellander-Edman
authors.forename: Karim
authors.initials: K
authors.lastname: Makdoumi
authors.forename: Jes
authors.initials: J
authors.lastname: Mortensen
authors.forename: Björn
authors.initials: B
authors.lastname: Ekesten
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003315:Cornea / Q000473:pathology; D003320:Corneal Ulcer / Q000382:microbiology / Q000473:pathology / Q000532:radiotherapy / Q000662:veterinary*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D015818:Eye Infections, Bacterial / Q000188:drug therapy / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000473:pathology / Q000532:radiotherapy*; D006736:Horses; D008297:Male; D012256:Riboflavin / Q000627:therapeutic use*; D014467:Ultraviolet Therapy / Q000379:methods / Q000662:veterinary*
chemical_list: D000900:Anti-Bacterial Agents; D003432:Cross-Linking Reagents; D012256:Riboflavin